For several reasons it may be desirable to dampen oscillations in such structures. Oscillations cause mechanical stress in the structures which may ultimately damage the structure itself. Human beings may experience discomfort when subjected to oscillations and equipment that is subject to oscillations may be caused to malfunction or even be damaged by oscillations.
JP 2001 020850 A and U.S. Pat. No. 5,233,797 both disclose a system for damping one-dimensional oscillations in wind turbine towers. A movable mass is set into simple linear oscillations.